It is known from U.S. Pat. No. 3,498,868 to bond a flange of a plastics pouring spout to a two-ply thin gauge plastics film of a bag. An annular area of an axially inner surface of a flange of the spout is so selected for heating that the non-heated areas surrounding or close to the heated area are sufficient to prevent distortion of the shape of the flange, thus maintaining the flange in the shape in which it has been moulded. At this heated area is a sufficient mass of plastics material that a heat reservoir is created which maintains some of the initially supplied heat while the fitment is being moved from a flange-heating station to a joining station where the plastics film is to be applied. The heat carried is sufficient that merely a sufficiently light pressure to only maintain contact between the engaged film and the heated area will be adequate to achieve a joining between the two. At the flange-heating station the spout is lifted by a plunger into contact with an electrical, annular, heating element, to apply the element to the area to be heated; the surface temperature of the element is above the fusion temperature of the plastics of the flange so as quickly to heat this annular area above its melting point [for example may be approximately 193xc2x0 C. (380xc2x0 F.) with polyethylene (PE)] and yet, it is stated, the flange is so supported by the non-heated areas of the flange and the plunger surface that the spout remains undistorted. The contact of the element with the flange is of a short duration consistent with lack of distortion of the plastics material of the flange. In some cases, it may be necessary to apply heat to the plastics material from both sides. At the joining station, the spout is raised by another plunger through an opening in the film and an annular pressing element is brought into light contact with the film to urge it against the flange. If the flange and the two-ply film thicknesses are such that the flange does not have enough heat at engagement to completely activate the thin film, a minimum amount of heat would be added to the film, as for example 127xc2x0 C. (260xc2x0 F.) for PE by providing electrical heating of the pressing element. The heat provided by the latter electrical heating is equal to or less than the heat applied to the flange at the flange-heating station and the pressure is very light. The heat will be only sufficient to cause the plastics film to become fluid or mobile, sufficient heat having been retained in the heated part of the flange so that, over a short dwell time, molecular diffusion will take place on the interface and thereby provide a weld or joining of the parts one to the other. Although the temperature applied to the flange may be well above the melting point of the flange, the subsequent heat at the point of joining of the thin plastic film and the flange will be only sufficient to have an interfacial temperature in the fluid region of the plastics. Under some conditions, where an extremely thin plastics film is to be joined, sufficient heat may be available from the thick flange to achieve fluidity in the film without the application of heat at the joining station.
U.S. Pat. No. 3,231,444 discloses a method of heat-sealing a thermoplastic pour spout fitment to the exterior surface of one of two adjacent sheets of thermoplastic material to form a bag. A length of thermoplastic bag tubing is heat-sealed at both ends. The fitment and the tubing are of compatible materials. Radiant heat, for example from an infra-red heater bar, is directed at the bottom surface of the fitment, which surface is formed with an annular rib, or a plurality of concentric annular ribs. Heat can also be provided by a hot plate in contact with the rib(s). The heat is applied for a length of time sufficient to reduce the rib(s) to a softened or molten state, appropriate for heat sealing. The fitment is then pressed against the outer surface of an upper wall of the bag, for example by means of an appropriately shaped anvil. To reduce the possibility of adherence at the interface of the two walls of the bag, a water-cooled chamber is placed in contact with the outer surface of the lower wall so as to conduct heat away from the interface. The or each rib, which is continuous so as to provide a liquid-tight seal between the bag and the fitment, is thereby fused to the outer surface of the upper wall of the bag. Immediately prior to filling the bag, the bag wall at the opening of the fitment is punctured to permit filling of the bag through the fitment and then the fitment is closed by a cap. The fitment surface against which the heat is directed is of a large area relative to the cross-sectional area of the rib(s), so that only the rib(s) is/are reduced to a softened or molten state.
Hereto, pour spout fitments have been secured to thermoplastic-coated container panels by various methods.
In U.S. Pat. No. 4,813,578, the following method is employed: A mandrel is inserted into the interior of the still-open mouth of the container, with the mandrel abutting the interior surface of a barrier layer and forming a back-up support. Hot air or radiant heat is applied to the external surface of a gable top wall immediately around an opening to thereby soften the polyethylene coating, with a pour spout fitment flange placed on the softened layer to thereby adhere the flange to the wall. An external mandrel is also employed to press the assembly against the internally positioned mandrel. This pressure is maintained until the coating cools and thereby effects permanent adhesion of the flange to the wall. U.S. Pat. No. 4,813,578 discloses that other methods, such as ultrasonic adhesion and impulse heating, may be employed.
U.S. Pat. No. 5,249,695 merely recites that attachment to the polymer-coated paperboard panel is accomplished by welding or otherwise adhering a spout fitment flange to the polymer coating.
U.S. Pat. No.5,110,041 discloses that dual lanes of pour spout fitment sealing apparatus are integrated in line with conventional form/fill/seal production lines. Pre-sided carton blanks are opened to tube configurations and placed in flight pockets on an indexing conveyor for step-wise advance to each fitment sealing apparatus. At the sealing apparatus, the fitments are gravity-fed down a track and released one-by-one by an escapement to a pair of fitment retaining clamps positioned in front of the spout hole of each carton blank advanced to the sealing apparatus. A timing control causes the clamps to move apart at the same time as an ultrasonic sealing horn advances to press the fitment into contact with the outside thermoplastics layer of the blank and an anvil is inserted into the blank. The horn is energized to seal the fitment to the blank, the horn and the anvil are retracted, and the clamps are moved back to receive the next fitment. In an alternative embodiment, the fitment is sealed to the outside layer by hot-metal adhesive which is applied to the sealing surface of the fitment just prior to pressing the fitment against the outside layer. Heat may be applied to tackify the adhesive by a hot anvil or sealing head equipped with heating elements.
U.S. Pat. No. 4,964,562 and U.S. Pat. No. 5,152,438 each utilize an ultrasonic sealing horn and a back-up support mandrel operative around respective pouring apertures.
U.S. Pat. No. 4,948,015 discloses the use of an ultrasonic horn to bond a flange of a pour spout fitment to an inner or back surface of a container panel around a pouring aperture.
U.S. Pat. No. 4,669,640 suggests fusing a pour spout flange to an inside surface of a carton gable top either thermally or ultrasonically.
U.S. Pat. No. 5,088,643 states that a pour spout fitment is preferably adhered to the outer surface of a container panel by impulse heating under pressure such as ultrasonic sealing although other methods may be used as desired.
DE-A-3838739 discloses a method in which a thermoplastic disc is applied to the outside thermoplastic layer of the laminate of the container so that the middle of the disc is sealed to the thermoplastic inside layer of the container through an opening through the paperboard layer. Then the disc is heated so that it becomes plastic and a tubular spout is inserted into the opening so that the thermoplastics of the disc is sealingly present between the inner edge of the opening and the outside of the spout.
U.S. Pat. No. 4,925,034, WO-A-93/02923 and WO-A-95/21734 disclose adhesively bonding a pour spout fitment by a hot melt glue to a top outer surface of a container. W093/02923 discloses a method which includes applying a hot-melt adhesive to a fitment, allowing the adhesive to solidify, introducing the fitment to a fitment applicator machine, indexing the fitment through a heating station of the machine, and reactivating the adhesive by radiant pre-heating and convection final heating thereat, mechanically picking up the fitment, introducing the filled and sealed container to the machine, and conveying the container to a position in which the fitment is placed on a container and attached thereto. After indexing through the heating station, where the hot-melt adhesive is reactivated, the fitments approach a rotating turret wheel via a heating station conveyor where they are grasped by pick-up devices mounted on the turret. The pick-up devices transfer the fitments to the containers where the fitments are then held in place on the containers by the pick-up devices until the fitments are fully adhered. The machine may be equipped with a programmed control system to indicate fault conditions. Various malfunctions may be indicated, such as: vibrating track (for fitments) empty, feeder hopper (for fitments) empty, hopper low, fitment jam, low temperature, low air pressure, downstream jam, etc.
U.S. Pat. No. 5,101,999 suggests that a spout or closure be attached to a package too by any suitable means such as an adhesive applied to a bottom surface of the closure to be attached to the package top; it also suggests, where the package is coated with an outer thermoplastic layer of polyethylene, which discourages such adhesion, the use of perimeter cuts which may be serrated or applied as perforated cuts. Such serrations or perforated cuts need only penetrate the polyethylene outer layer to allow the adhesive to bond with the underlying carrier or paper layer.
U.S. Pat. No. 4,507,168 discloses attaching a pour spout fitment to the outside of a roof panel of a filled and sealed gable-top carton. A heater is inserted into a space between the fitment and the roof panel and heats both the bottom surface of the thermoplastics fitment and the outside thermoplastics coating of the roof panel; the heater is then withdrawn and the bottom surface of the fitment is applied to the outside coating.
According to one aspect of the present invention, there is provided a method of attaching an article to a thermoplastic layer of a laminate without using hot-melt adhesive, the method comprising the steps of:
providing an article;
heating a thermoplastic portion of the article;
placing that heated portion of the article on a portion of the thermoplastic layer to heat and thus activate said portion of the thermoplastic layer, said portion of the article being of a thermal capacity higher than that of said portion of the layer; and
allowing or causing the heated portions of the article and the layer to cool, to thereby become bonded together;
characterized in that said heating is to a temperature no higher than the melting point of the thermoplastic of said portion of the article.
Owing to this aspect of the invention, it is possible to avoid the serious risk of distortion of the thermoplastic portion of the article which arises if that portion is heated to higher than the melting point of its thermoplastic. It is, surprisingly, feasible to heat that portion to a temperature no higher than one significantly below the melting point of its thermoplastic and still obtain good bonding together of the portions in question.
According to a second aspect of the present invention, there is provided a method of attaching an article to a thermoplastic material without using hot-melt adhesive, the method comprising the steps of:
providing an article in the form of a pour spout fitment;
heating a thermoplastic portion of the article, said heating being without contact between any heating member and said portion of the article;
placing that heated portion of the article on a portion of the thermoplastic material to heat and thus activate said portion of the thermoplastic material, and
allowing or causing the heated portions of said article and said material to cool, to thereby become bonded together,
characterized in that said thermoplastic material is a thermoplastic coating on a paperboard layer of a laminate in the form of an erected container.
Owing to this aspect of the invention, at is possible to avoid the serious risk of distortion of the thermoplastic portion of the pour spout fitment which arises if that portion is contacted by a heating member. Furthermore, there is less need for the heating means to be shaped to suit the shape of the fitment. Radiant heating or direct heating by streams of hot gaseous fluid is particularly suitable.
According to a third aspect of the present invention, there is provided a method of attaching an article to a thermoplastic material without using hot-melt adhesive, the method comprising the steps of:
providing an article;
heating a thermoplastic portion of the article;
placing, by placing means, that heated portion of the article on a portion of the thermoplastic material to heat and thus activate said portion of the thermoplastic material, and
allowing or causing the heated portions of said article and said material to cool, to thereby become bonded together,
characterized in that said allowing or causing is accompanied by advancing said article, said thermoplastic material and said placing means in unison.
According to a fourth aspect of the present invention, there is provided apparatus for use in attaching an article to a thermoplastic material without hot-melt adhesive, comprising:
heating means for heating a thermoplastic portion of said article; and
placing means for placing that heated portion of the article on a portion of said material to heat and thus activate said portion of said material;
characterized by advancing means for advancing said material along a path; and
driving means connected to said placing means for displacing said placing means and thus said article along said path in unison with said material.
Owing to these aspects of the invention, it is possible to ensure that the article becomes reliably bonded to the thermoplastic material even if the material is being advanced at a relatively high rate during cooling; not only can the placing means serve to hold the article in a fixed position relative to the advancing material, but it can be provided with cooling means which can cool the heated portions as they advance.
According to a fifth aspect of the present invention, there is provided apparatus for use in attaching an article to a thermoplastic material, comprising:
advancing means for advancing said material along a path;
heating means for heating a thermoplastic portion of said article;
placing means for placing that heated portion of the article on a portion of said material to heat and thus activate said portion of said material;
material-loading means arranged to load said material onto said advancing means; and
article-loading means arranged to load said article onto said placing means;
characterized by material-detecting means arranged to detect said material in correct position ready for loading onto said advancing means;
and article-detecting means arranged to detect said article in correct position ready for loading onto said placing means;
the arrangement being such that neither said material-loading means nor said article-loading means is operable unless said material-detecting means detects such correctly positioned material and said article-detecting means detects such correctly positioned article.
Owing to this aspect of the invention, it is possible to avoid either of the article and the material being loaded when the other is not in its correct position ready for loading.
Preferably, cooling means is connected to the placing means for cooling the placing means and thereby the heated portions of the article and the material, the placing means being cooled throughout the heating, and also subsequently to cause the heated portions of the article and the material to cool, to thereby become bonded together. In this manner, the cooling serves the two purposes of preventing overheating of the placing means and of causing bonding together of the article and the material.
The advancing may be continuous or indexed and may be linear or rotary.
The invention is particularly applicable to securing a thermoplastic article to a thermoplastic coating of a laminate, in particular securing a thermoplastic, pour spout fitment to a thermoplastic-coated container. Preferably, at least an anchoring flange of the pour spout fitment is heated remotely by a suitable heating mechanism, to a predetermined temperature below the melting point of the thermoplastic of the flange, such that, when the fitment is applied to a selected surface of the thermoplastic-coated container, the thermal energy is transferred to the latter surface at a rate capable of activating the thermoplastic coating; upon cooling, the fitment and the container surface bond together. Although the present system can be employed to fix the fitment to the container before filling of the container, it is particularly applicable downstream of any forming, filling and sealing apparatus for the container.